Currently, hands-free access requests mainly consists of the need to position a hand in order to confirm a request for opening/closing an access to a vehicle, and this process comprises two main steps: recognition of a key or a badge authorized to open or close the vehicle near to the access by the BCM of the access system and, in the case of a request for opening, detection of the presence of the hand on a handle.
The implementation of this method necessitates antennas for the detection of authorized keys or badges, contact sensors in the handles, in general capacitive sensors, for the detection of a hand, together with a centralized system for management of the hands-free access requests, which may for example be a computer wholly or partially dedicated to this function.
With regard to the use of the foot for contactless opening, one known application relates to the opening of an operating theater door for hospital staff. The utility model CN 202 143 044 for example provides for the door to be equipped with an inductive sensor for detection of a foot. People wishing to enter or to exit from the theater extend their foot near to the sensor and the signal detected by the sensor is transmitted to a device for controlling a mechanism for opening/closing of the door.
Use of the foot for a hands-free access to the trunk of an automobile is presented in the international patent application WO 2012/052210. This document provides the detection of a movement of a part of the body of the user, for example the foot, by a capacitive detection assembly with two elongated electrodes. These electrodes run horizontally under the trunk, the longer underneath the shorter, and are coupled to a control and evaluation device. The variations of capacitance are monitored with respect to a reference potential, and when the movement is in the detection range, an activation is triggered, for example the opening of the trunk.
The management of the accesses to a vehicle in the framework of the requests for hands-free access using hand detection has been improved in order to combat various interference effects. For example, the patent document FR 2 827 064 aims to identify the interference effects generated by the metallic paints of automobiles by a module for logical interpretation of the durations of the signals received.
One solution provided to the problem of electromagnetic interference is described in the patent document FR 2 915 331. A time-related filtering is provided for the signals coming from the sensors in the access handles, in order to validate or otherwise the presence of a hand on a handle prior to validating a request for opening.
The system for hands-free opening/closing of the prior art therefore offers an appreciable comfort for users, with a confirmation of opening/closing of an access given by the presence of a hand or by a foot movement. However, false detections such as those resulting from interference effects caused by atmospheric phenomena, in particular rain, or other types (electromagnetic interference, objects passing under the bumper, etc.) are not identified and unexpectedly trigger a spurious request for opening. Solutions exist for overcoming certain interference effects for opening/closing operations using the hand, but no reliable solution exists for foot movement detection systems. Even if, in the latter case, the detection system is based on two sensors per access, the system has not been made sufficiently reliable in a noisy environment.